Increasing channel capacity in fixed cellular networks

ABSTRACT

A method of forwarding signals over a cellular link. The method includes receiving, at a first base station of a cellular fixed network, a packet of signals having a data payload directed to a second base station, determining whether the data payload will be used by the second base station, and forwarding the entire packet if the data payload will be used and not forwarding the entire packet if the data payload will not be used.

FIELD OF THE INVENTION

The present invention relates to wireless communication networks andparticularly to increasing the channel capacity of cellular networks.

BACKGROUND OF THE INVENTION

Cellular fixed networks are generally formed of a plurality of basetransceiver stations (BTSs) which wirelessly contact mobile units(referred to also as mobile stations and/or cellular handsets), servicedby the network. The BTSs are connected, usually in a tree topology, to aregional base station controller (BSC) which controls the routing ofcalls in the network. In the tree topology, one or more of the BTSs areconnected directly to the BSC, and the other BTSs connect to the BSCthrough other BTSs which serve as relay units. The links of the tree areformed of cables which comprise a predetermined number of channelsaccording to the capacity of the link. Each channel includes bandwidthsufficient for passing the signals of a single telephone call at therate of 16 Kbit/sec. A commonly used link is the E1 link which includes120 channels. Alternatively, each channel includes bandwidth sufficientfor passing the signals of a single telephone call at the rate of 8Kbit/sec, and in such a case an E1 link includes 240 channels.

When a mobile unit participates in a telephone call, the BSC allocates,using circuit switching, a connection from the BSC to the BTS servicingthe mobile. The allocated connection is formed of dedicated channelswhich are used only for signals passed to and from the mobile unit towhich the connection was allocated, and the allocation remains in effectuntil the telephone call is terminated. During the call, the mobile unitconverts input signals into digital signals. As the use of wirelessbandwidth is very costly, the digital signals are compressed by themobile unit, and the compressed signals are transmitted to the servicingBTS. Generally, every 20 msec the mobile unit generates a packet of 320bits which represents the sounds collected by the mobile unit during atime period of 20 msec.

The servicing BTS passes the compressed signals as they are, withoutdecompressing them, to the BSC, over the mobile's dedicated channels.The BSC usually decompresses the signals and transfers them to a Mobileswitching Center (MSC) or to a public network to which the signals aredirected.

Generally, each packet comprises a header and a payload. Exemplaryheaders are formed of 8 synchronization bits and 24 control bits or of16 synchronization bits and 16 control bits. It is noted that otherheader structures exist, including encapsulations which distribute thecontrol bits throughout the packets.

With the increase in usage of cellular phones the number of callscarried out concurrently by a single BTS and the number of concurrentlyallocated channels on a single link increased substantially. As thesignals sent from the BTSs to the BSC are already compressed, furthercompression would degrade the signals below current quality standards.

Therefore, in order to supply the demand, additional cables and/orcables of larger bandwidth must be laid between the BSC and the BTSs. Insome densely populated areas the laying of cables may be very costly.

SUMMARY OF THE INVENTION

An aspect of some preferred embodiments of the invention relates toidentifying needless packets which are being passed over a connectionthe needless packets carry data which will not be used by the entity(e.g., BSC, BTS, mobile unit) to which the packets are directed. Thedata of these packets is not sent over the connection, thus reducing theload on the links hosting the connection. The needless packets aregenerated, for example, by a mobile unit or BTS in order to representthe sound signals at a time when the user of the mobile unit is notgenerating sounds (e.g., the user is listening to another partyparticipating in the call).

Preferably, each link serves as one or more tunnels which pass packetsfrom a plurality of mobile units assigned to the tunnel. Each tunnel isassigned a number of connections larger than the number of channels inthe tunnel, based on that statistical average percentage of needlesspackets.

Packets passed through a tunnel are passed on one or more of thechannels of the tunnel which channels are selected irrespective of thesource, contents and destination of the packet. Thus, packets from asingle source to a single destination which are passed through a tunnelmay pass through different channels of the tunnel, and packets fromdifferent sources and to different destination may pass on the samechannel of the tunnel. In a preferred embodiment of the invention, eachpacket header is tagged with an identity tag which states to whichconnection the packet belongs, as the channel on which the packet ispassed does not identify the channel. Alternatively or additionally,signaling bits not attached to the packets are used to state theconnections to which the packets belong.

In a preferred embodiment of the invention, the needless packets areidentified according to control bits in their header. Alternatively oradditionally, the needless packets are identified based on controlsignals sent on a signaling line corresponding to the link on which thepackets are passed. Further alternatively or additionally, the needlesspackets are identified based on their contents, e.g., packets which areall ‘1’s.

An aspect of some preferred embodiments of the present invention relatesto a base transmission station (BTS) which has an amount of bandwidthfor receiving packets greater than the amount of bandwidth it has onlinks for forwarding packets. Preferably, the BTS and/or an externalcompression unit statistically compress the received packets onto thelinks it uses for forwarding packets.

There is therefore provided in accordance with a preferred embodiment ofthe invention, a method of forwarding signals over a cellular link,including receiving, at a first base station of a cellular fixednetwork, a packet of signals having a data payload directed to a secondbase station, determining whether the data payload will be used by thesecond base station, and forwarding the entire packet if the datapayload will be used and not forwarding the entire packet if the datapayload will not be used.

Preferably, receiving the packet includes receiving a stream of packetsof the same size at equal intervals of time. Alternatively, receivingthe packet includes receiving a packet which includes coded digitalvoice signals. Preferably, determining whether the data payload will beused by the second base station includes determining whether thecontents of the payload will be decoded.

In a preferred embodiment of the invention, determining whether the datapayload will be used by the second base station includes determiningwhether the second base station will forward the contents of thepayload. Alternatively or additionally, determining whether the datapayload will be used is dependent on information retrieved from asignaling line corresponding to the link. Alternatively or additionally,determining whether the data payload will be used is dependent oninformation retrieved from a header of the packet. Alternatively oradditionally, determining whether the data payload will be used isperformed before forwarding any part of the packet.

Alternatively, determining whether the data payload will be used isperformed after forwarding at least part of the packet. Preferably, notforwarding the entire packet if the data payload will not be usedincludes forwarding less than the entire packet. Preferably, forwardingless than the entire packet includes forwarding only a header of thepacket. Preferably, forwarding the entire packet includes forwardingthrough a tunnel used by a plurality of connections.

In a preferred embodiment of the invention, not forwarding the entirepacket if the data payload will not be used includes not forwarding anyof the packet. Preferably the method includes forwarding a message inplace of a plurality of packets not forwarded.

In a preferred embodiment of the invention, forwarding the entire packetincludes forwarding the packet along with a connection indication field.Alternatively or additionally, forwarding the entire packet includesforwarding through a tunnel used by a number of connections greater thanthe number of channels in the tunnel.

In a preferred embodiment of the invention, the first base station andthe second base station include base transmission stations. In apreferred embodiment of the invention, the first base station includes abase station controller.

There is also provided in accordance with a preferred embodiment of theinvention, a method of forwarding signals over a link between basestations, including receiving, at a first base station of a cellularfixed network, a plurality of packets, and forwarding the entire packetof at least one of the packets and not forwarding the entire packet ofat least one of the packets. Preferably, receiving the plurality ofpackets includes receiving packets of a plurality of mobile units thepackets of each mobile unit being received at a fixed rate.Alternatively or additionally, forwarding the entire packet of at leastone of the packets includes forwarding the entire packet of less than apredetermined percentage of the received packets.

There is also provided in accordance with a preferred embodiment of theinvention, a method for decompressing packets being forwarded over alink between base stations, including receiving signals belonging to aplurality of connections, forwarding packets which were received intheir entirety, and generating replacement packets in place of packetsnot received in their entirety.

There is also provided in accordance with a preferred embodiment of theinvention, apparatus for compressing packets being forwarded over a linkbetween base stations, including an input interface which receivespackets having a data payload, a processor which determines whether thedata payload carries meaningful information, and an output interfacewhich forwards the entire packet if the data payload carries meaningfulinformation and does not forward the entire packet if the data payloaddoes not carry meaningful information. Preferably, the processor whichdetermines whether the data payload carries meaningful information alsogenerates the packets. Alternatively or additionally, the processorexamines a header of the packets to determine whether the data payloadis meaningful.

In a preferred embodiment of the invention, the output interface beginsto forward the packets before the processor determines whether the datapayload is meaningful.

In a preferred embodiment of the invention, the apparatus includes adelay unit which delays forwarding the packets while the processordetermines whether the data payload is meaningful.

There is also provided in accordance with a preferred embodiment of theinvention, apparatus for decompressing packets being transmitted over alink between base stations, including an input interface which receivessignals belonging to a plurality of connections, a forwarding unit whichforwards packets which were received in their entirety, and a processorwhich generates replacement packets in place of packets not received intheir entirety. Preferably, the processor generates replacement packetsfrom received headers. Alternatively or additionally, the processorgenerates a plurality of replacement packets based on a single message.Preferably, the processor generates a plurality of replacement packetsof different connections based on a single message.

There is also provided in accordance with a preferred embodiment of theinvention, a system for forwarding packets from and to mobile units,including a base transmission station which generates a stream ofpackets each having a data payload, a compression unit which determineswhether the data payload carries meaningful information, forwards theentire packet of packets which carry meaningful information and does notforward the entire packet of packets which do not carry meaningfulinformation, and a base station controller which receives the forwardedpackets and generates replacement packets for packets not forwarded intheir entirety.

There is also provided in accordance with a preferred embodiment of theinvention, apparatus for forwarding packets through a fixed cellularnetwork, including a base transmission station having an interface tomobile units which receives packets of up to a total first amount ofbandwidth, one or more first links, having a total second amount ofbandwidth, through which the base transmission station receives packets,and one or more second links, having a total third amount of bandwidthwhich is smaller than the sum of the first and second amounts ofbandwidth, through which the base transmission station forwards packets.Preferably, the third amount of bandwidth is smaller than the secondamount of bandwidth. Alternatively or additionally, the basetransmission station statistically compresses the packets receivedthrough the interface of the mobile units and through the one or morefirst links, into the second links.

In a preferred embodiment of the invention, a compression unit externalto the base transmission station statistically compresses the packetsreceived through the interface of the mobile units and through the oneor more first links, into the second links.

There is also provided in accordance with a preferred embodiment of theinvention, a telecommunication system operative in a cellular network,including one or more first base stations, each connected to a secondbase station via first transmission paths having first bandwidths, wheresaid first bandwidths may be equal or different from each other, and athird base station connected to said second base station via a secondtransmission path having a second bandwidth which is substantially lowerthan the sum of said first bandwidths.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clearly understood by reference to thefollowing description of preferred embodiments thereof in conjunctionwith the figures, in which:

FIG. 1 is a schematic illustration of a portion of a cellular network,in accordance with a preferred embodiment of the present invention;

FIG. 2 is a flow chart of the actions performed on packets passing alonga cellular fixed network, in accordance with a preferred embodiment ofthe present invention;

FIG. 3 is a schematic flow chart of the actions performed duringstatistical compression of packets in a cellular fixed network, inaccordance with a preferred embodiment of the present invention; and

FIG. 4 is a schematic illustration of a voice packet, in accordance witha preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a schematic illustration of a portion of a cellular network20, in accordance with a preferred embodiment of the invention. Network20 comprises a plurality of base transceiver stations (BTSs) 24 whichwirelessly contact mobile units 26 serviced by network 20. BTSs 24 areconnected to a regional base station controller (BSC) 22, through aplurality of links 28 which comprise cable wires (e.g. the E1 link), orother communication links, such as wireless omnidirectional links. Eachlink comprises one or more tunnels which are formed of a plurality ofchannels. In the following description it is assumed that each link 28accommodates a single tunnel including all the channels of the link. Aplurality of statistical compression and decompression units 30 arelocated at the interfaces to the BTSs 24 and to BSC 22 in order tostatistically compress and decompress the transmitted signals, asdescribed hereinbelow. Each unit 30 preferably comprises a compressionunit 32 for signals which it transmits and a decompression unit 34 forsignals it receives.

Preferably, each tunnel is assigned a maximal number of virtualconnections which the tunnel may service. The maximal number of virtualconnections is preferably larger than the number of channels in thetunnel because of the statistical compression. When a mobile unit 26initiates or receives a telephone call, BSC 22 allocates a virtualconnection along a path of links 28 from the mobile unit to the BSC.

FIG. 2 is a flow chart of the actions performed on packets passing froma BTS 24A to BSC 22, in accordance with a preferred embodiment of thepresent invention. For each mobile unit 26 serviced by BTS 24A, BTS 24Apreferably generates packets of 320 bits every 20 milliseconds (40). Thepackets pass through the compression unit 32A of BTS 24A whichstatistically compresses (42) the packets into a tunnel on link 28A. Thepackets are preferably passed (44) over link 28 to BTS 24B whichtransfers the packets intact to link 28B. The packets on link 28B arepreferably decompressed (46) by decompression unit 34C and are providedto BSC 22.

FIG. 3 is a flow chart of the actions performed during statisticalcompression of packets, in accordance with a preferred embodiment of thepresent invention. Compression unit 32 receives each packet andpreferably tags (52) a connection identification to the packet accordingto the virtual connection to which the packet belongs. Unit 32preferably finds (54) an unused channel within the tunnel to which thevirtual connection is assigned and begins to transmit (56) the headerand/or the tag of the packet on that channel. If there are no availableunused channels, the packet is preferably discarded (66). Unit 32preferably determines (58) whether the packet is needless, i.e., whetherthe data carried by the packet will be read by BSC 22 (whether the datais meaningful). If the data will be read, the entire packet ispreferably transmitted (60). However, if the data will be ignored, onlythe header and tag are transmitted (62).

Alternatively, only part of the header is transmitted, preferably thatpart of the header which is required in order to reconstruct the entirepacket. In a preferred embodiment of the invention, all thesynchronization bits in the header are transmitted together with some ofthe control bits of the header.

Preferably, determination 58 is concluded before the header (or thetransmitted part of the header) is transmitted. Alternatively, thetransmission of the header is delayed such that the determination isconcluded before transmission of the header is finished. Furtheralternatively, if the determination is not concluded before the headeris entirely transmitted, unit 32 begins transmitting the data of thepacket. If after beginning to transmit the data, the packet isdetermined to be needless, the transmission is terminated and thechannel is preferably immediately considered available for transmissionof a different packet. Alternatively, when the determination requiresmore time than the transmission occurs relatively rarely, the entirepacket is transmitted in such cases, although the packet is needless.

Referring in more detail to determining (58) whether the data carried bythe packet will be read by BSC 22, in a preferred embodiment of theinvention, unit 32 listens to a signaling line 36 (FIG. 1) correspondingto link 28. If signaling line 36 indicates that no voice data is beingpassed on a specific connection the packets of that connection areneedless and therefore are discarded.

Alternatively or additionally, compression unit 32 consults the controlbits of the header of the packet to determine whether the data of thepacket should be discarded. Preferably, the data of the packet isdiscarded if a bad frame indicator, e.g., bit C12 in the header,indicates that the packet is defective. Alternatively or additionally,the data of the packet is discarded if the header indicates that thepacket is idle, e.g., bits C1-C5 of the header are all ones. Furtheralternatively or additionally, the data of the packet is discarded ifthe header indicates discontinuation of transmission, e.g., bit C17 isset.

Further alternatively or additionally, compression unit 32 consults thepayload of the packet to determine whether the data of the packet willbe discarded. In a preferred embodiment of the invention, when thepayload comprises one or more patterns used for padding needlesspackets, e.g., a packet formed of all ‘1’s, the packet is discarded. Itis noted that in this alternative, unit 32 preferably delays thereceived packets for the length of an entire packet in order todetermine whether the packet is to be transmitted. Therefore, thisalternative is preferably used only when such delay is acceptable.

Reference is now made in more detail to tagging (52) the packet with theconnection identification. FIG. 4 is a schematic illustration of a voicepacket 80, in accordance with a preferred embodiment of the presentinvention. Packet 80 when it is created preferably comprises a header 82having 32 bits and a data payload 84 having 288 bits. Header 82preferably comprises 16 synchronization bits 86 and 16 control bits 88.In tagging a connection identification, unit 30 preferably adds aconnection field 90 which contains the number of the virtual connectionto which the packet belongs. Field 90 preferably includes the smallestnumber of bits required to uniquely identify the maximal number ofconnections accommodated by link 28. For E1 links which include 120channels, field 90 preferably includes eight bits. It is noted that theabove mentioned sizes of header 82 and payload 84, as well as thenumbers of synchronization bits 86 and control bits 88 are brought hereby way of example and substantially any other sizes and bit numbers maybe used with the present invention.

Field 90 is preferably located after the synchronization bits 86anywhere in header 82. Alternatively, field 90 is located or distributedwithin payload 84 or at the end of packet 80. Alternatively oradditionally, field 90 states the identity of the BTS 24 to which thepacket is destined or the route of BTSs through which the packet is topass. Further alternatively or additionally, signaling line 36 is usedto state the connection to which each packet belongs.

Referring back to the decompression (48 in FIG. 2) performed bydecompression unit 34C, when a packet is received, the connectionindication bits of field 90 are removed. If the packet includes only aheader, decompression unit 34C creates a fictitious payload, e.g., apayload formed entirely of ‘1’s. It is noted that the header serves asan indication to reconstruct the packet.

In some preferred embodiments of the invention, unit 32 beginstransmitting (56 in FIG. 3) the header of the packet before it isdetermined (58) whether the data of the packet is to be transmitted.Thus, the delay incurred by unit 32 is minimized.

Alternatively to sending the header to represent the packet which is notsent, a special message is sent representing one or more packets whichare not sent. In this alternative, unit 32 preferably delays thereceived packets for a sufficient time required to determine whether thepackets are to be transmitted. In a preferred embodiment of theinvention, one or more special messages are sent to represent all thepackets which are not sent over a predetermined period, e.g., 10 msec.Preferably, the special message states the connections to which theunsent packets belong, and any important information in their headers,such as the types of the packets (e.g., speech, data, idle, bad frame).Upon receiving the special message, decompression unit 34C reconstructsthe packets according to the contents of the special message.

Further alternatively to sending the headers of unsent packets,compression unit 32 sends a special message notifying that packets willnot be sent on a connection which is generating needless packets, for apredetermined period or until further notice. The special messagepreferably includes instructions on how to reconstruct the packets indecompression unit 34C.

Further alternatively or additionally, compression unit 32 does not sendanything instead of messages which include payload which will not beread, and decompression unit 34C generates packets for activeconnections for which packets were not received.

In some preferred embodiments of the invention, before a packet isdiscarded (66) because all the channels are in use, compression unit 32waits a predetermined time, e.g., a few msec, in case one of thechannels becomes available. Alternatively or additionally, unit 32 keepstrack of the timing of all the channels in the tunnel and determineswhether one of the channels will become available within thepredetermined time. In a preferred embodiment of the invention, unit 32chooses the packet to be discarded based on priorities of theconnections. Preferably, the connections are assigned priority levels,and the discarded packets are preferably packets from the lowestpriority received within the predetermined period.

Alternatively or additionally, the connection from which packets arediscarded, is a connection which its previous packets were needlesspackets.

Further alternatively or additionally, the connection from which packetsare discarded is chosen according to the time for which the connectionis active. In a preferred embodiment, the discarded packets are from theconnection established last. In a preferred embodiment of the invention,a mobile unit 26 requesting to establish a connection when only a lastfew connections are available is notified that the connection isestablished conditionally. The user of the requesting mobile unit, mayestablish the call anyhow or may defer the call to a laser time. Inanother preferred embodiment, the discarded packets belong to theearliest established connection.

In some preferred embodiments of the invention, instead of discarding(66) a packet, only the header of the packet is transmitted as describedabove with relation to needless packets.

In some preferred embodiments of the invention, the maximal number ofconnections on a single tunnel is chosen based on the number of channelsin the tunnel and the average a percentage of needless packets.Preferably, the maximal number of connections includes a safety marginsuch that packets are discarded only rarely, as the discarding ofpackets causes interference in the connection and/or abrupt ending ofthe connection. In a preferred embodiment of the invention, the size ofthe safety margin depends on the number of channels in the tunnel.Preferably, the size of the safety margin depends on the inverse of thenumber of channels in the tunnel.

In a preferred embodiment of the invention, if BSC 22 determines thatpackets are being discarded it temporarily lowers the number ofconnections allowed in the tunnels in order to prevent furtherdiscarding of packets. Thus, after one of the connections isdisconnected, under the initiative of the user or due to packetdiscarding, new connections are not allowed to take its place.Alternatively, connections which were disconnected due to discarding ofpackets are allowed to re-connect while new connections are not allowedto connect until a sufficient number of connections are terminated.

In some preferred embodiments of the invention, compression anddecompression unit is an integral part of its respective BTS 24.Preferably, the combined BTS 24 does not create the payload of needlesspackets, and/or during decompression does not generate a fictitiouspayload. Alternatively or additionally, in order to keep BTSs 24 simple,units 30 are separate from BTSs 24 but a unit 30 is an integral part ofBSC 22.

In a preferred embodiment of the invention, the signals are compressedby the unit 32 of the BTS 24 directly servicing the mobile unit 26generating the signals, and are decompressed only at their entrance toBSC 22. On there passage through intermediate BTSs 24 and units 30 thesignals preferably remain intact. Alternatively or additionally, foreach link 28 which the signals pass the signals are compressed anddecompressed.

In a preferred embodiment of the invention, each link comprises a singletunnel which includes all the channels of the link. Preferably, thesingle tunnel serves all the types of data to and from mobile units 26,including voice and data packets. Alternatively or additionally, one ormore of links 28 comprise a plurality of tunnels. In a preferredembodiment of the invention, at least some of links 28 comprise a firsttunnel for voice packets and a second tunnel for data packets. Thetunnel for data packets is preferably managed as described in U.S.patent application Ser. No. 09/430,985, titled “Data Transmission onWireless Network” and filed on Nov. 1, 1999, the disclosure of which isincorporated herein by reference.

In a preferred embodiment of the invention, one or more links 28 has oneor more tunnels for packets from mobiles 26 directly connected to a BTS24 incident on the link, and has different one or more tunnels forpackets received by the BTS incident on the link from other BTSs.Alternatively or additionally, packets from mobile units 26 with highquality of service are passed through a first tunnel and other datapackets are passed through a second tunnel.

The term tunnel refers, in the present application and claims, to agroup of channels which are correlated such that a packet entering thetunnel may pass through any of the channels (one or more) included inthe tunnel regardless of the source, contents and destination of thepacket.

In the above description it was assumed that the tunneling of packetsinto the tunnel is performed by selecting a free channel and sendingeach packet on a single channel. It is noted, however, that thistunneling method is not necessary and substantially any other method oftunneling may be used in accordance with the present invention. It isfurther noted that the present invention can be implemented withsubstantially any type and size of links and with substantially anytransmission rate on the links, including links allowing a plurality ofdifferent transmission rates. Numbers describing sizes of links andtransmission rates thereon are brought only by way of example.

It is noted that the principles of the present invention apply both totransmission from the mobile unit to the BSC and to transmission fromthe BSC to the mobile unit. Although some of the above descriptionsrelate to transmission in only one direction, these descriptions pertainas well to transmission in the other direction.

It will be appreciated that the above described methods may be varied inmany ways, including, changing the order of steps, and the exactimplementation used. It should also be appreciated that the abovedescribed description of methods and apparatus are to be interpreted asincluding apparatus for carrying out the methods and methods of usingthe apparatus.

The present invention has been described using non-limiting detaileddescriptions of preferred embodiments thereof that are provided by wayof example and are not intended to limit the scope of the invention. Itshould be understood that features described with respect to oneembodiment may be used with other embodiments and that not allembodiments of the invention have all of the features shown in aparticular figure. Variations of embodiments described will occur topersons of the art. Furthermore, the terms “comprise,” “include,” “have”and their conjugates, shall mean, when used in the claims, “includingbut not necessarily limited to.” The scope of the invention is limitedonly by the following claims:

1. A method of forwarding signals over a cellular link, comprising thesteps of: receiving, at a first base station of a cellular fixednetwork, a packet of signals having a data payload, wherein the packetis directed to a second base station; determining whether the datapayload will be decoded by the second base station ; and forwarding thedata payload of the packet if the data payload will be decoded and notforwarding the entire data payload of the packet if the data payloadwill not be decoded.
 2. A method according to claim 1, wherein receivingthe packet comprises receiving a stream of packets of the same size atequal intervals of time.
 3. A method according to claim 1, whereinreceiving the packet comprises receiving a packet which includes codeddigital voice signals.
 4. A method according to claim 1, whereindetermining whether the data payload will be decoded by the second basestation comprises determining whether the second base station willforward or discard the contents of the payload.
 5. A method according toclaim 1, wherein determining whether the data payload will be decodedcomprises determining based on information retrieved from a header ofthe packet.
 6. A method according to claim 1, wherein determiningwhether the data payload will be decoded is performed before forwardingany part of the packet.
 7. A method according to claim 1, wherein notforwarding the entire payload of the packet if the data payload will notbe decoded comprises not forwarding any of the packet.
 8. A methodaccording to claim 7, comprising forwarding a message in place of aplurality of packets not forwarded.
 9. A method according to claim 1,wherein forwarding the payload of the packet comprises forwarding thepacket along with a connection indication field.
 10. A method accordingto claim 1, wherein forwarding the payload of the packet comprisesforwarding through a tunnel used by a number of connections greater thanthe number of channels in the tunnel.
 11. A method according to claim 1,wherein the first base station and the second base station comprise basetransmission stations.
 12. A method according to claim 1, wherein thefirst base station comprises a base station controller.
 13. A methodaccording to claim 1, wherein not forwarding the entire payload of thepacket if the data payload will not be decoded comprises forwarding lessthan the entire payload of the packet.
 14. A method according to claim13, wherein forwarding less than the entire payload of the packetcomprises forwarding only a header of the packet.
 15. A method accordingto claim 1, wherein forwarding the data payload of the packet if thedata payload will be decoded comprises forwarding the entire packet. 16.A method according to claim 1, wherein forwarding the data payload ofthe packet if the data payload will be decoded comprises forwarding thecontent of the payload of the packet.
 17. A method of forwarding signalsover a cellular link, comprising: receiving, at a first base station ofa cellular fixed network, a packet of signals having a data payload,wherein the packet is directed to a second base station; determiningwhether the data payload will be used based on information retrievedfrom a signaling line corresponding to the link; and forwarding the datapayload of the packet if the data payload will be used and notforwarding the entire data payload of the packet if the data payloadwill not be used.
 18. A method according to claim 1 17, whereindetermining whether the data payload will be used is performed afterforwarding at least part of the packet.
 19. A method according to claim18 17, wherein not forwarding the entire payload of the packet if thedata payload will not be used comprises forwarding less than the entirepayload of the packet.
 20. A method according to claim 19, whereinforwarding less than the entire payload of the packet comprisesforwarding only a header of the packet.
 21. A method according to claim20 17, wherein forwarding the payload of the packet comprises forwardingthrough a tunnel used by a plurality of connections.
 22. Apparatus forcompressing packets being forwarded over a link between base stations,comprising: an input interface which receives packets having a datapayload; a processor which determines whether the data payload carriesmeaningful information and will be decoded by a remote base station; andan output interface which forwards the payload of the packet if the datapayload carries meaningful information and will be decoded by the remotestation and does not forward the entire packet if the data payload doesnot carry meaningful information.
 23. Apparatus according to claim 22,wherein the processor which determines whether the data payload carriesmeaningful information also generates the packets.
 24. Apparatusaccording to claim 22, wherein the processor examines a header of thepackets to determine whether the data payload is meaningful. 25.Apparatus according to claim 22, wherein the output interface begins toforward the packets before the processor determines whether the datapayload is meaningful.
 26. Apparatus according to claim 22, comprising adelay unit, which delays forwarding the packets while the processordetermines whether the payload is meaningful.
 27. Apparatus forcompressing packets being forwarded over a link between base stations,comprising: a first input interface for receiving packets having a datapayload, wherein the data payload comprises a compressed signal that wascompressed by an initiator of the data payload; a second input interfacefor receiving information from a signaling line corresponding to thelink carrying the data payload; a processor which determines whether thedata payload carries meaningful information, based on informationreceived from the signaling line; and an output interface which forwardsthe payload of the packet if the data payload carries meaningfulinformation and does not forward the entire packet if the data payloaddoes not carry meaningful information.
 28. Apparatus according to claim22, wherein the processor determines whether the data payload isdefective to determine whether the data payload is meaningful. 29.Apparatus according to claim 22, wherein the processor determineswhether the data payload includes padding needless information todetermine whether the data payload is meaningful.
 30. Apparatusaccording to claim 22, wherein the processor determines whether thecellular link is discontinued to determine whether the data payload ismeaningful.
 31. Apparatus according to claim 22, wherein the initiatorof the data payload is a mobile phone.
 32. Apparatus according to claim22, wherein the entity to which the data payload is directed to is amobile phone.
 33. A method of forwarding signals over a cellular link,further comprising the steps of: receiving, at a first base station of acellular fixed network, a packet of signals having a data payload,wherein the data payload is directed to an entity, and wherein the datapayload comprises a compressed signal that was compressed by aninitiator of the data payload; determining whether the data payload willbe read; and forwarding the data payload of the packet if the datapayload will be read and not forwarding the entire data payload of thepacket if the data payload will not be read.
 34. A method according toclaim 33, wherein determining whether the data payload will be readfurther comprises the step of determining whether the data payload willbe read by the entity.
 35. A method according to claim 34, wherein theentity to which the data payload is directed is a second base station.36. A method according to claim 35, wherein the second base station is abase station controller.
 37. A method according to claim 35, wherein thesecond base station is a mobile switching center.
 38. A method accordingto claim 35, wherein determining whether the data payload will be readcomprises determining whether the second base station will forward ordiscard the contents of the payload.
 39. A method according to claim 33,wherein the entity to which the data payload is directed is a mobilephone.
 40. A method according to claim 33, wherein the first basestation of a cellular fixed network comprises at least one base stationselected from a group consisting of base transceiver station, basestation controller, and mobile switching center.
 41. A method accordingto claim 33, wherein receiving the packet comprises receiving a packetwhich includes coded digital voice signals.
 42. A method according toclaim 33, further comprising the step of: retrieving information from aheader of the packet, wherein at least a portion of the retrievedinformation is used in determining whether the data payload will beread.
 43. A method according to claim 33, wherein determining whetherthe data payload will be read is performed before forwarding any part ofthe packet.
 44. A method according to claim 33, wherein not forwardingthe entire payload of the packet if the data payload will not be readcomprises not forwarding any of the packet.
 45. A method according toclaim 44, further comprising the step of forwarding a message in placeof a plurality of packets not forwarded.
 46. A method according to claim33, wherein forwarding the payload of the packet comprises forwardingthe packet along with a connection indication field.
 47. A methodaccording to claim 33, wherein forwarding the payload of the packetcomprises forwarding through a tunnel used by a number of connectionsgreater than the number of channels in the tunnel.
 48. A methodaccording to claim 33, wherein not forwarding the entire payload of thepacket if the data payload will not be read comprises forwarding lessthan the entire payload of the packet.
 49. A method according to claim48, wherein forwarding less than the entire payload of the packetcomprises forwarding only a header of the packet.
 50. A method accordingto claim 33, wherein forwarding the data payload of the packet if thedata payload will be read comprises forwarding the entire packet.
 51. Amethod according to claim 33, wherein forwarding the data payload of thepacket if the data payload will be read comprises forwarding the contentof the payload of the packet.
 52. A method according to claim 33,wherein the initiator of the data payload is a mobile telephone.
 53. Amethod according to claim 33, wherein determining whether the datapayload will be read is performed after forwarding at least part of thepacket.
 54. A method of forwarding signals over a cellular link,comprising: receiving, at a first base station of a cellular fixednetwork, a packet of signals having a data payload, wherein the packetis directed to a second base station, wherein the data payload comprisesa signal that was compressed by an initiator of the data payload;determining whether the data payload should be discarded; and forwardingthe data payload of the packet if the data payload should not bediscarded and not forwarding the entire data payload of the packet ifthe data payload should be discarded.
 55. A method according to claim54, wherein determining whether the data payload should be discardedcomprises determining based on information retrieved from a header. 56.A method according to claim 54, wherein determining whether the datapayload should be discarded comprises determining whether the datapayload is defective.
 57. A method according to claim 54, whereindetermining whether the data payload should be discarded comprisesdetermining whether the cellular link is discontinued.
 58. A methodaccording to claim 54, wherein determining whether the data payloadshould be discarded comprises determining whether the data payloadincludes padding needless information.
 59. A method according to claim54, wherein the initiator of the data payload is a mobile telephone.